PB2662: ABO BLOOD GROUP TYPE AND RISK OF VENOUS THROMBOEMBOLISM IN PATIENTS WITH LYMPHOMA
Authors: Vladimir Otasevic, Jelena Ivanović, Vojin Vukovic, Sofija Sarac, Biljana Mihaljevic, Darko Antic
Journal: HemaSphere (2023)

Topic: 34. Thrombosis and vascular biology - Biology & Translational Research Background: Risk of venous thromboembolism (VTE) is increased in patients with cancer owing to various pathophysiological mechanisms that generate prothrombotic state. Lymphoma patients are well known to be at significant risk for VTE development. The rate of VTE in lymphoma patients depends on numerous factors, with highest rates being observed in patients with aggressive non-Hodgkin lymphoma (NHL). Recently, non-O blood type was associated with increased risk of VTE in patients with cancer and it has been proposed as time-dependent predictor of VTE in that group of patients. Aims: The aim of the study was to examine ABO blood group as a risk factor for VTE development in patients with lymphoma. Methods: A total of 600 patients with lymphoma (newly diagnosed and relapsed) have been included in the study. All the patients have been treated at Lymphoma Center, Clinic for Hematology, University Clinical Center of Serbia. Data regarding VTE events was collected for all the patients included in the study, from the time of diagnosis to 3 months after the last cycle of therapy. ABO blood group has been determined prior to treatment initialization through standard institutional procedure. VTE was diagnosed objectively based on radiographic studies (duplex venous ultrasound, contrast-enhanced thoracic computed tomography scan, magnetic resonance imaging - for central nervous system thrombosis, clinical examination, and laboratory evaluation. All probable cases of VTE were reviewed and confirmed by a at least two specialists (internist and radiologist). Results: The median patients’ age was 57 years (range, 18–89 years); 55.5% were males. The majority of the patients were newly diagnosed (88.8%). The distribution of the diagnosis was following: indolent NHL 140 (23.3%), aggressive NHL 366 (61%), and Hodgkin lymphoma 94 (15.7%), respectively. Most of the patients included in the study had advanced stage (III stage Ann Arbor 21.5% and IV 40.3%) of the disease. The rate of VTE was 10.3% (62 patients), with the highest rate in aggressive NHL group of patients (7.7%, 46 patients). VTE was diagnosed before the specific hematological treatment initiation in 46.8% of lymphoma patients, whilst 53.2% of lymphoma patients have been diagnosed with VTE after the hematological treatment commencement. A blood type was the most common in our group of patients (41.6%), followed by O blood type (33.3%), B blood type (15.8%) and AB blood type (9.3%), respectively. There was no statistically significant association between VTE development and ABO group type (p=0.495; the rate of VTE in patients with A blood type was 3.8%, in B blood type 1.5%, in AB blood type 1.5% and in O blood type 3.5%, respectively). Non-O blood type lymphoma patients with VTE had significantly more often developed VTE prior to the treatment initiation in comparison with O blood type lymphoma patients with VTE (2.5% vs. 1%, p=0.04, respectively), whereas VTE in O blood type lymphoma patients was significantly more often after the initiation of hematological treatment in comparison with VTE in non-O blood type patients (3.8% vs. 3%, p=0.04). Logistic regression model demonstrated that non-O blood type is a predictor of pre-treatment VTE development in lymphoma patients (odds ratio (OR)=3.19, confidence interval (CI): 1.03-9.88, p=0.044). Summary/Conclusion While there is no association between frequency of ABO blood group and the rate of VTE in lymphoma patients, non-O blood type in lymphoma patients has shown to be a predictor of VTE development prior to specific hematologic treatment commencement. Keywords: Hodgkin’s lymphoma, ABO blood group, Non-Hodgkin’s lymphoma, Venous thromboembolism